PHP面向对象编程简单实例

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1.静态属性用于保存类的公有数据
2.静态方法里面只能访问静态属性
3.静态成员不需要实例化对象就可以进行访问
4.类的内部可以通过self或者static关键字访问自身静态成员
5.可以通过parent关键字访问父类的静态成员
6.可以通过类的名称在类定义外部访问静态成员

<span style="color: #008000">*/

<span style="color: #0000ff">class<span style="color: #000000"> Human{

<span style="color: #0000ff">public <span style="color: #800080">$name<span style="color: #000000">;

<span style="color: #0000ff">protected <span style="color: #800080">$height; <span style="color: #008000">//<span style="color: #008000">只有自身和子类可以访问

<span style="color: #0000ff">public <span style="color: #800080">$weight<span style="color: #000000">;

<span style="color: #0000ff">private <span style="color: #800080">$isHungry = <span style="color: #0000ff">true; <span style="color: #008000">//<span style="color: #008000">不能被子类访问


<span style="color: #0000ff">public <span style="color: #0000ff">static <span style="color: #800080">$sValue = "Static value in Human class"."n"<span style="color: #000000">;
<span style="color: #0000ff">public <span style="color: #0000ff">function eat(<span style="color: #800080">$food<span style="color: #000000">){

<span style="color: #0000ff">echo <span style="color: #800080">$this->name."'s eating "."'<span style="color: #800080">$food"."n"<span style="color: #000000">;

}
<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> info(){

<span style="color: #0000ff">echo "HUMAN :".<span style="color: #800080">$this->name. ";".<span style="color: #800080">$this->height.";".<span style="color: #800080">$this->isHungry."n"<span style="color: #000000">;

}

}

<span style="color: #0000ff">class<span style="color: #000000"> Animal{
}
<span style="color: #008000">//<span style="color: #008000">类的定义以关键字class开始,后面是类的名称，类的命名通常第一个字母大写，以中括号开始和结束

//在PHP中用extends关键字表示类的继承，后面跟父类的类名

//PHP中extends后只能跟一个类的类名，这是PHP中的单继承原则

<span style="color: #0000ff">class NBaplayer <span style="color: #0000ff">extends<span style="color: #000000"> Human

{

<span style="color: #008000">//<span style="color: #008000"> public $name = "Jordan"; //定义属性

// public $height = "198cm";

// public $weight = "98kg";

<span style="color: #0000ff">public <span style="color: #800080">$team = "Bull"<span style="color: #000000">;

<span style="color: #0000ff">public <span style="color: #800080">$playernumber = "23"<span style="color: #000000">;
<span style="color: #0000ff">private <span style="color: #800080">$age = "40"; <span style="color: #008000">//<span style="color: #008000">Private的类成员只能在内部被访问
//静态属性在定义时在访问控制关键字后面添加static关键字即可

<span style="color: #0000ff">public <span style="color: #0000ff">static <span style="color: #800080">$president = "David Stern"<span style="color: #000000">;

<span style="color: #008000">//<span style="color: #008000"> 静态方法在定义时在访问控制关键字后面添加static关键字即可

<span style="color: #0000ff">public <span style="color: #0000ff">static <span style="color: #0000ff">function changePresident(<span style="color: #800080">$newpresdt<span style="color: #000000">){

<span style="color: #008000">//<span style="color: #008000">在类定义中使用静态成员时，用self或者static关键字后面跟::操作符即可

//注意，在访问静态成员属性时，::后面需要跟$符号

self ::<span style="color: #800080">$president = <span style="color: #800080">$newpresdt<span style="color: #000000">;

<span style="color: #008000">//<span style="color: #008000">使用parent关键字访问父类中的静态成员

<span style="color: #0000ff">echo parent::<span style="color: #800080">$sValue."n"<span style="color: #000000">;

}
<span style="color: #008000">//<span style="color: #008000">构造函数，在对象被实例化时自动调用

<span style="color: #0000ff">function __construct(<span style="color: #800080">$name,<span style="color: #800080">$height,<span style="color: #800080">$weight,<span style="color: #800080">$team,<span style="color: #800080">$playernumber<span style="color: #000000">)

{

<span style="color: #0000ff">echo "in NBaplayer constuctorn"<span style="color: #000000">;

<span style="color: #800080">$this->name = <span style="color: #800080">$name; <span style="color: #008000">//<span style="color: #008000">$this是php里面的伪变量，表示对象自身，可以通过$->this的方式访问对象的属性和方法

<span style="color: #800080">$this->height = <span style="color: #800080">$height<span style="color: #000000">;

<span style="color: #800080">$this->weight = <span style="color: #800080">$weight<span style="color: #000000">;

<span style="color: #800080">$this->team = <span style="color: #800080">$team<span style="color: #000000">;

<span style="color: #800080">$this->playernumber = <span style="color: #800080">$playernumber<span style="color: #000000">;

<span style="color: #0000ff">echo <span style="color: #800080">$this->height."n"<span style="color: #000000">;

}
<span style="color: #008000">//<span style="color: #008000">析构函数，在程序执行结束时自动调用

//析构函数通常被用于清理程序使用的资源。比如，程序使用了打印机，那么可以在析构函数里释放打印机资源

<span style="color: #0000ff">function<span style="color: #000000"> __destruct()

{

<span style="color: #0000ff">echo "Destroying ".<span style="color: #800080">$this->name."n"<span style="color: #000000">;

}
<span style="color: #008000">//<span style="color: #008000">定义方法

<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> run()

{

<span style="color: #0000ff">echo "runningn"<span style="color: #000000">;

}
<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> jump()

{

<span style="color: #0000ff">echo "jumpingn"<span style="color: #000000">;

}
<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> dribble()

{

<span style="color: #0000ff">echo "dribblingn"<span style="color: #000000">;

}
<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> shoot()

{

<span style="color: #0000ff">echo "shootingn"<span style="color: #000000">;

}
<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> dunk()

{

<span style="color: #0000ff">echo "dunkingn"<span style="color: #000000">;

}
<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> pass()

{

<span style="color: #0000ff">echo "passingn"<span style="color: #000000">;

}

<span style="color: #0000ff">public <span style="color: #0000ff">function<span style="color: #000000"> getAge(){

<span style="color: #0000ff">echo <span style="color: #800080">$this->name."'s age is ".(<span style="color: #800080">$this->age - 2)."n"<span style="color: #000000">;

}

}

<span style="color: #008000">//<span style="color: #008000">类到对象的实例化

//类的对象为实例化时使用关键字new,后面是类的名称和一堆括号

// $jordan = new NBaplayer("Jordan","198cm","98kg","Bull","23");

// $james = new NBaplayer("James","203cm","120kg","Heat","6");

//对象中的成员属性通过->符号来访问

//在类定义外部访问静态属性，可以用类名加::操作符的方法来访问类的静态成员

<span style="color: #0000ff">echo NBaplayer::<span style="color: #800080">$president." Before change"."n"<span style="color: #000000">;

NBaplayer::changePresident("Aadam Siver"<span style="color: #000000">);

<span style="color: #0000ff">echo NBaplayer::<span style="color: #800080">$president."n"<span style="color: #000000">;

<span style="color: #0000ff">echo Human::<span style="color: #800080">$sValue."n"<span style="color: #000000">;

<span style="color: #008000">//<span style="color: #008000"> echo "Jordan : ".$jordan->president."n";

// echo "James : ".$james->president."n";

<span style="color: #0000ff">echo <span style="color: #800080">$jordan->name."n"<span style="color: #000000">;

<span style="color: #008000">//<span style="color: #008000">echo $jordan->getAge();

// $jordan->info();

// $jordan->eat("Apple"); //在子类中的对象上可以直接访问父类中定义的属性和方法

//对象中的成员方法通过->符号来访问

// $jordan->dribble();

// $jordan->dunk();

// $jordan->jump();

// $jordan->pass();

// $jordan->run();

// $jordan->shoot();

//

// //每一次用new实例化对象的时候，都会用类名后面的参数列表调用构造函数

// $james = new NBaplayer("James","6");

// echo $james->name."n";
                        
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